MySQL Bugs: #119004: UNREACHABLE member is not expelled after the group_replication_member_expel

Bug #119004	UNREACHABLE member is not expelled after the group_replication_member_expel_timeout delay
Submitted:	12 Sep 2025 16:07	Modified:	12 Jan 9:12
Reporter:	Garrido Mickael	Email Updates:
Status:	No Feedback	Impact on me:	None
Category:	MySQL Server: Group Replication	Severity:	S2 (Serious)
Version:	8.0+	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
We're performing a MySQL upgrade from 8.0.x to 8.0.43 to several clusters. During the process, some members occasionally become UNREACHABLE, and in the logs of other members, we see messages like: 'Old incarnation found while trying to add node ...'.
According to the documentation, a member marked as UNREACHABLE should be evicted after the delay defined by the "group_replication_member_expel_timeout" variable. However, this never happens.
We use InnoDB Cluster with Group Replication, which relies on XCom for internal communication.
Are you aware of any issues related to this?
We’ve tried using removeInstance followed by addInstance or rejoinInstance, but none of those approaches worked. The only way we’ve been able to recover is by restarting the entire cluster.

How to repeat:
Create a cluster and upgrade to a minor version.

Hi,

I just did upgrade few days ago of a 5 node innodb cluster from 8.0.35 to 8.0.43 without a glitch.

Can you share more data? (configuration, logs ..)

Thanks

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".